Discuss about challenges in Ethereum blockchain transaction and sharding? foe 2 marks

Ethereum blockchain transactions face several challenges:

1. Scalability: The Ethereum network can only process a limited number of transactions per second, which can lead to congestion and slow transaction times during periods of high demand. This is a significant challenge as it limits the potential for Ethereum to be used on a large scale.

2. High transaction fees: The cost of executing transactions on the Ethereum network, known as "gas fees," can be quite high, especially during periods of congestion. This can make it expensive to perform transactions or execute smart contracts.

3. Network upgrades: Ethereum is in the process of upgrading to Ethereum 2.0, which will introduce significant changes to the network, including the introduction of sharding. This upgrade process is complex and carries the risk of unforeseen complications or delays.

Sharding is a proposed solution to Ethereum's scalability problem. It involves splitting the Ethereum network into smaller pieces, or "shards," each capable of processing its own transactions and smart contracts. However, sharding also presents several challenges:

1. Inter-shard communication: Transactions that affect multiple shards will need to be carefully coordinated to ensure consistency across the network. This is a complex problem and a potential source of security vulnerabilities.

2. Data availability: Sharding can make it more difficult to ensure that all nodes in the network have access to all the data they need. This could potentially lead to a more centralized network, which would be contrary to Ethereum's decentralized ethos.

3. Complexity: Sharding adds a significant amount of complexity to the Ethereum network, which could lead to unforeseen problems or make the network more difficult to understand and use.